Stainless Steels in warm, damp and chlorine environments.

[SteamyTea]

Youtube has some great resources on it.

 

 

[JohnMo]

Yep

[Onoff]

Grade A2 nuts and bolts, by the sea, end up like a Swiss cheese. A4 is what you want.

[JohnMo]

16 minutes ago, Onoff said:

Grade A2 nuts and bolts, by the sea, end up like a Swiss cheese. A4 is what you want.

But not in a warm chlorine environment, still not good enough.

[SteamyTea]

Chlorine can be produced from seawater quite easily with electrolysis.

[JohnMo]

30 minutes ago, SteamyTea said:

Chlorine can be produced from seawater quite easily with electrolysis.

It is routinely for offshore rig and ships, it uses plastic and titanium components.

[SteamyTea]

Just now, JohnMo said:

It is routinely for offshore rig and ships, it uses plastic and titanium components.

What is, making chlorine or preventing it being made?

[JohnMo]

25 minutes ago, SteamyTea said:

What is, making chlorine or preventing it being made?

Making chlorine - rigs make chlorine and add to the cooling water - this is generally seawater. The chlorine is to kill stuff and act as biocide. Otherwise you get mussels etc growing within the heat exchangers.

 

The chlorine makers take seawater, the by products are highly corrosive, the off gas from the process is hydrogen.

 

Generally chlorine making is a very simple, but at the same time a very unreliable process.

[Onoff]

I know using stainless electrodes for electrolysis isn't a good idea as it produces toxic hexavalent chromium, Cr6+ at the anode.

 

It does work mind as I've tried it. 

[Alan Ambrose]

That’s all a bit concerning, but are there implications for self build?

[SteamyTea]

59 minutes ago, Alan Ambrose said:

That’s all a bit concerning, but are there implications for self build?

Why I posted it up.

[JohnMo]

1 hour ago, Alan Ambrose said:

That’s all a bit concerning, but are there implications for self build?

Are you using stainless steel fasteners or structural elements?

 

Are you in a high chlorine area (directly next to or on the sea)?

 

Are these elements exposed to a salt spray or chlorinated air atmosphere?

 

Do you have these fasteners or structural elements exposed to above ambient temperature conditions?

 

If you answer no to all the above - no issues. If you answer yes to all of the above, you have issues to address.

 

Stainless steel has zero place for structural elements or fasteners in almost all situations.

[SteamyTea]

3 hours ago, JohnMo said:

Stainless steel has zero place for structural elements or fasteners in almost all situations

PV installations use them.

[JohnMo]

53 minutes ago, SteamyTea said:

PV installations use them.

Stainless steel screws in aluminium is another corrosion issue waiting to happen.  The stainless steel is using the aluminium as a sacrificial anode.

[Onoff]

6 hours ago, JohnMo said:

Stainless steel has zero place for structural elements or fasteners in almost all situations.

 

Hasn't A4 80 roughly the same tensile strength as Gr8.8 mild steel?

[SimonD]

7 hours ago, JohnMo said:

Stainless steel has zero place..fasteners in almost all situations.

 

SS is used for traditional metal standing seam roof clips and screws.

[JohnMo]

Similar tensile, A4 has a lower yield than 8.8. Stainless is also very susceptible to galling. But 8.8 is the minimum standard for anything structural, depending on exact application.